Pressure reducer with adjustable flow restrictor

ABSTRACT

A pressure reducer has a housing comprising an inlet and an outlet in which a flow-around body is arranged in a flow channel connecting inlet and outlet. A flow restrictor is adjustably mounted relative to the flow-around body for varying a flow rate and is movably connected with an adjusting means comprising a recirculating ball nut and a rotating spindle wherein the rotating spindle is movably connected with said flow restrictor. To improve such a pressure reducer that a corresponding flow restrictor with a facilitated construction is reliable and can exactly be adjusted in position, the recirculating ball nut is detachably fastened to a turning sleeve rotatably mounted in the flow-around body and the recirculating ball nut is connected with a driving toothed wheel in a rotation-resistant manner, which is rotatable by an electric drive for the movable connected with recirculating ball nut.

The invention relates to a pressure reducer with a housing comprising aninlet and an outlet, in which a flow-around body is arranged in a flowchannel connecting inlet and outlet, wherein a flow restrictor isadjustably mounted relative to the flow-around body for varying a flowrate and is movably connected with an adjusting means.

Such a pressure reducer is known from DE 34 09 973. Such pressurereducers serve to regulate the flow rate of fluids, gases and/ormixtures of solid matters, and they are particularly arranged in theconveyor pipelines for oil recovery or natural gas extraction. Such apressure reducer can be mounted in the conveyor pipeline as a separatecomponent, and can be operated automatically, manually or via remotecontrol. The individual parts of the pressure reducer are fabricatedfrom particularly resistant materials, as the wear would otherwise betoo high, for example, with oil/sand mixtures in the conveyor pipelines.

The flow-around body is disposed in the corresponding housing of thepressure reducer, and a needle serving as flow restrictor can be pushedout of the flow-around body so as to vary the flow rate. According to DE34 09 973 the needle is associated with a hydraulic drive, for which anumber of hydraulic pipelines are required for charging and dischargingthe corresponding hydraulic fluid.

The invention is based on the object to improve a pressure reducer ofthe aforementioned type such that a corresponding flow restrictor with afacilitated construction is reliable and can exactly be adjusted andpositioned.

In connection with the features according to the preamble of claim 1said object is provided in that the adjusting means comprises arecirculating ball nut rotatably mounted in the flow-around body andfixed substantially in an axial direction, as well as a rotating spindlemounted axially adjustable in the same, whereby the rotating spindle ismovably connected with the flow restrictor.

By rotating the recirculating ball nut, the rotational movement thereofis converted into an axial movement of the rotating spindle, by whichthe flow restrictor is adjusted so as to vary the flow rate. Therecirculating ball nut of the adjusting means can be rotated manually,automatically or also by remote control.

Such a threaded spindle-nut-drive formed by the recirculating ball nutand the rotating spindle is an excellent machine element for convertinga rotary into a translatoric movement. Such an adjusting means has avery good mechanical efficiency due to the small rolling friction and nostick-slip effect. Moreover, the wear is extremely small and results ina long service life. Eventually, the heating is very small, and such anadjusting means brings about a high accuracy in view of positioning andrepetition, namely due to zero backlash, and a high traverse rate.

By means of the adjusting means according to the invention, moreover,strong forces can be transmitted, so that a secure and exact positioningof the flow restrictor for adjusting a selected flow rate is feasiblealso at high pressures in the flow channel.

For being able to accommodate the recirculating ball nut in the housingwithout having to perform laborious changes to the construction thereof,the recirculating ball nut may be fixed in a detachable fashion in aturning sleeve rotatably mounted in the flow-around body. The turningsleeve more or less serves as an adapter for arranging the recirculatingball nut or, respectively, the entire adjusting means inside thehousing. If the recirculating ball nut and the turning sleeve aredetachably fastened, the recirculating ball nut can be easily dismountedand can be handled separately for the maintenance thereof or the like.

In order to be able to well associate and fix the recirculating ball nutand the turning sleeve with each other, the turning sleeve may beprovided with a radially inwardly, at least partially projectingshoulder, to which a radially outwardly projecting contact flange of therecirculating ball nut can closely be fitted. Thus, the relativeposition between the recirculating ball nut and the turning sleeve isexactly defined.

For further simplifying the mutual attachment, the shoulder and thecontact flange can be detachably connected with each other. Thus, theshoulder and the contact flange not only serve the relative positioning,but at the same time the attachment of both components.

For fixing the recirculating ball nut directly by the turning sleeve inan axial direction, the turning sleeve may be fixed in an axialdirection.

For being capable of accommodating the adjusting means and the turningsleeve in the housing in an easy manner, the housing may comprise aninterior space in which the driving means and the turning sleeve aredisposed.

In order to realize, in this connection, the rotatable mounting of theturning sleeve and the recirculating ball nut in an easy manner, a pivotbearing means can be arranged between the outer wall of the turningsleeve and the wall of the interior space of the flow-around body.

A simple embodiment for such a pivot bearing means can be seen in thatthe same at least comprises one ball bearing. The ball bearing ispreferably arranged along the outer circumference of the turning sleeveand is correspondingly fixed in the interior space.

The fixing may especially be performed by detachably fastening the pivotbearing means on the wall of the interior space.

A possibility for fastening the pivot bearing means, which canespecially also absorb axial forces, can be seen in that the pivotbearing means fits closely to a shoulder of the wall at one of its endsand is attached, at its other end, relative to the wall at least in anaxial direction. Said attachment at its other end may be removable, sothat the pivot bearing means or, respectively, the at least one ballbearing can be removed easily.

A possibility for attaching the pivot bearing means on the wall isprovided by associating a retaining ring at the other end of the pivotbearing means, which can be inserted in a corresponding groove in thewall of the interior space and retains the pivot bearing in contact withthe shoulder of the wall.

In order to hold the turning sleeve on the pivot bearing stationary inan axial direction, a ring nut may externally be screwed onto a screwingend of the turning sleeve. In the corresponding functional position ofthe turning sleeve said ring nut fits closely to the pivot bearing meansand prevents a displacement of the turning sleeve relative to the pivotbearing means.

For fixing the turning sleeve at both ends of the pivot bearing means inan axial direction the turning sleeve may be provided with a radiallyoutwardly projecting stop spaced apart from the screwing end and fittingclosely to the pivot bearing means opposite the ring nut. It is alsopossible, however, that the turning sleeve is fixed opposite the ringnut on the wall of the interior space, for example, by correspondingshoulders fitted closely thereto.

For being able to differently position and fix the turning sleeverelative to the pivot bearing means in an axial direction, a spacer ringmay be arranged between the stop and the pivot bearing means. Saidspacer ring may have different thicknesses in response to the desiredrelative position between the turning sleeve and the pivot bearingmeans.

For adjusting the flow restrictor the rotating spindle can directly beconnected to the same. For being able to adjust, in dependence on theneed, flow restrictors of different sizes and/or with differentdistances therebetween without having to modify the ball nut and thethreaded spindle, the rotating spindle may be connected with anactuating piston, which is detachably connected with the flowrestrictor. By the axial movement of the threaded spindle the actuatingpiston is likewise displaced in an axial direction correspondingly. Onits end facing the flow restrictor the actuating piston may be designedto match the flow restrictor so as to produce a mutual connection. Independence on the need, the actuating piston may moreover be chosen tohave a corresponding length so as to connect flow restrictors positionedmore closely or further away relative to the driving means with therotating spindle.

The connection between the actuating piston and the rotating spindle maytake place in different ways. For example, the actuating piston may bescrewed onto the rotating spindle from the outside. Another example forthe mutual attachment may be seen in that the rotating spindle and theactuating piston are engaged at their ends facing each other in aform-fitted manner and/or are screwed together. In this connection, thescrewing may be realized with a corresponding stud or the like, which isscrewed transversely to the axial direction into the ends of therotating spindle and the actuating piston facing each other therebyconnecting the same.

The flow restrictor may be designed differently. It may, for instance,be a needle as is described in DE 3409974. Moreover, the flow restrictormay be an axially movable perforated panel.

For being able to easily realize different flow rates with such aperforated panel, holes with different diameters may be formed in theperforated panel in an axial direction. Depending on the arrangement ofthe corresponding holes, the flow between the flow channel and theoutlet is, therefore, differently large. In this connection it ispossible that, for instance, a number of holes having the same diameterare each formed in the perforated panel along a line perpendicularly tothe axial direction. In response to the movement of the perforated panelrelative to the flow channel and the outlet the connection thereof isproduced by holes having a corresponding diameter. The flow rate isvaried in response to the diameters of the different holes.

A simple realization of such a perforated blend may be seen in that thesame is designed as a hollow cylinder with holes arranged in thecylinder wall. The holes may, for instance, be arranged at identicalintervals in the circumferential direction of the cylinder and may eachhave the same diameter along a circumferential line.

For being able to easily connect the hollow cylinder with the rotatingspindle or the actuating piston, the hollow cylinder may comprise on itsend facing the flow-around body an insertable cylinder being axiallymovable in a bearing bore. The rotating spindle and the actuating pistonare connectable with said insertable cylinder. Moreover, thedisplacement of the insertable cylinder in the bearing bore results in afavorable guidance for the flow restrictor.

For facilitating the production of the flow restrictor the hollowcylinder and the insertable cylinder may have identical outer diameters.The flow restrictor may be made integrally and from a correspondingwear-resistant material.

For securely guiding the hollow cylindrical portion of the flowrestrictor, in addition to the guidance of the insertable cylinder inthe bearing bore, the hollow cylinder can be displaceably mounted in acylindrical section of the outlet. Thus, the flow restrictor can moreeasily withstand the possibly high pressures in conveyor pipelinesespecially for the recovery of oil.

For being able to securely seal the flow channel against the outlet inthe area of the flow restrictor, an inner wall of the cylindricalportion of the outlet may be formed by a sealing sleeve preferably madeof metal.

For allowing a discharge out of the outlet of the housing intosubsequent portions of a conveyor pipeline or the like as irrotationalas possible the outlet may be conically expanded downstream of thecylindrical portion.

A simple possibility of connecting the rotating spindle or the actuatingpiston with the flow restrictor is to screw a free end of the actuatingpiston or the rotating spindle into an end bore of the insertablecylinder.

In order to exactly define a corresponding screwed position the end boremay be provided with a shoulder fitting closely to the free end or to ashoulder being apart from the free end in the screwed position.

For preventing the flow restrictor from turning relative to the insertbore or, respectively, to the actuating piston or the rotating spindle,a guide bore may be formed parallel to the end bore in the insertablecylinder, with which a guide pin is displaceably engaged.

For preventing that fluid penetrates into the bearing bore from the flowchannel or the outlet, at least one sealing member can be disposedbetween the insertable cylinder and the inner wall of the bearing bore.

On the other hand, the fluid subjected to high pressure may also be usedfor supporting an axial displacement of the flow restrictor by thedriving means, for instance, by that a flow channel intersperses theinsertable cylinder in an axial direction. Through said flow channel thefluid may penetrate into the bearing bore so as to prevent that, given adisplacement of the flow restrictor against the pressurization by thefluid, a correspondingly high advance force has to be applied by thedriving means only.

For being able to arrange the different components of the driving meansand also of the flow restrictor in or on the flow-around body, theflow-around body may be composed of one central body and two end bodies.After the disassembly of the end bodies especially the interior space ofthe flow-around body is freely accessible, which is substantially onlyformed in the central body.

In order to design the flow-around body in a fashion favorable for theflow, at least the inlet end body facing the inlet may be substantiallyshaped like a circular cone.

The flow-around is moreover improved, if a cone point of the inlet endbody faces in the direction of the inlet and is arranged especiallycentrally to the inlet.

It is possible that the turning sleeve and/or the recirculating ball nutare at least partially arranged also in one of the end bodies. Forachieving an easy to handle unit it can be regarded as favorable,however, if at least the recirculating ball spindle and the turningsleeve are arranged in the substantially cylindrical central body.

For being able to accommodate the driving means in the central body in aprotected manner after the disassembly of the inlet end body, a lockingplate may be provided between the central body and the inlet end body.

For being able to securely operate the driving means according to theinvention automatically and especially remotely controlled, therecirculating ball nut can be movably connected with an electric drive.By said electric drive the recirculating ball nut is rotated togetherwith the turning sleeve, and said rotation is converted into atranslatoric movement of the rotating spindle and possibly the actuatingpiston and, thus, of the flow restrictor. The electric drive isprecisely controllable, so that the flow restrictor can be positionedexactly and reproducibly.

For transmitting a rotational movement to the recirculating ball nut inan easy fashion, the same may be connected with a driving toothed wheelin a rotation-resistant manner, with the driving toothed wheel berotatable by the electric drive. It is likewise possible that thedriving toothed wheel forms a part of the recirculating ball nut.

For being able, however, to exchange the driving toothed wheel, ifrequired, the same may be attached on the turning sleeve and/or therecirculating ball nut by means of a screw connection.

A simple possibility of realizing such an electric drive may be seen inthat the same comprises at least one electric motor.

For easily achieving corresponding transmission ratios between theelectric motor and the recirculating ball nut, and for rotating therecirculating ball nut with a possibly required high influence of forcesat the same time, the driving toothed wheel may be constructed as a wormgear engaged with a worm shaft driven by the electric motor. Such a wormgear may be designed to be self-locking, so that a rotation of the wormgear and/or worm shaft is impossible without an actuation of theelectric motor in both directions of rotation, or at least in onedirection of rotation. The worm gear and the worm shaft may be paireddifferently. For example, a cylinder worm may be paired with a globoidworm wheel, an enveloping worm may be paired with a spur gear, or anenveloping worm may be paired with a globoid worm wheel.

For constructing the electric drive to be as safe as possible againstfailure and/or for increasing a power transmission onto the worm shaft,the worm shaft can be movably connected with one electric motor each atits end sections. Such an electric motor can, for example, be a steppermotor or the like.

The end sections of the worm shaft may be connected with correspondingdrive shafts of the electric motors in a rotation-resistant manner. Itis, however, also possible that the end sections of the shaft aredirectly constructed as drive shafts of the electric motors.

For rotatably mounting the worm shaft in a secure manner therebyallowing it to absorb corresponding forces, the end sections of theshaft may be mounted adjacent to the electric motors. Such bearings maybe ball bearings and/or axial bearings.

For supplying, if necessary, all components inside the flow-around body,the flow-around body can comprise an outer sleeve with a radialextension extending at least to the inner wall of the flow channel.Electrical wires, supply lines, instrument leads or the like may bepassed therethrough. Moreover, the radial extension may also be appliedfor conducting the flow, by, for instance, sub-dividing the fluidflowing from the inlet to the outlet into corresponding partial flows.

In order to allow, in this connection, that as few whirls as possibleare formed during the flow in the radial extension, the same may bepointed at least at its end facing the inlet. The pointing Is designedsuch that it has a favorable effect on the flow.

As both aforementioned electric motors act on a shaft, a correspondingsynchronization is advantageous if both electric motors are operatedsimultaneously. This can, for example, be realized electronically or bymeans of software.

For being able to disassemble the housing of the pressure reduceraccording to the invention to an extent to allow, for instance, an easyremoval of the flow-around body, the housing can consist of two partsand the parts of the housing may be held together by a clamping ringalong their outer circumference.

For being able to supply and control the electric motors of the electricdrive directly from outside the flow-around body, the electric motorsand the worm shaft can be arranged in an outwardly open transverse boreextending substantially vertically to the rotating spindle.

For being thereby able to lay corresponding electrical wires or otherlines directly in the direction of the electric motors, the open ends ofthe transverse bore may each be associated with a radial extension ofthe outer sleeve, through which, again, corresponding electrical wires,supply lines, instrument leads or the like can be passed to the electricmotors from outside the housing, protected, by said radial extensions,against the fluid flowing around the flow-around body.

An advantageous embodiment of the invention will hereinafter beexplained by means of the attached figures, wherein

FIG. 1 shows a longitudinal section through an embodiment of a pressurereducer according to the invention, and

FIG. 2 shows a section along line II-II through FIG. 1.

FIG. 1 illustrates a longitudinal section through an embodiment of thepressure reducer 1 according to the invention. Said pressure reducer 1comprises a housing 4 formed of housing parts 74, 75. Said two parts ofthe housing are held together by a clamping ring 76 along their outercircumference.

The housing 4 comprises an inlet 2 at one end and an outlet 3 at theopposite end. Inside the housing 4, the inlet and the outlet areconnected with each other by means of a flow channel 6. A flow-aroundbody 5 is disposed in the flow channel 6. The flow-around body 5 isformed of a central body 52 and two end bodies 53, 54. The end body 53is associated with the inlet 2 as inlet end body and has the shape of acircular cone. A corresponding cone point 55 faces the inlet 2 and isarranged centrally thereto. The other end body 54 is constructed asoutlet end body in a substantially truncated fashion and comprises atits end facing outlet 3, substantially centrally, a bearing bore 37 openin the direction of the outlet 3.

A locking plate 56 is arranged between the inlet end body 53 and thecentral body 52, by which an interior space 14 of the central body 52 issealed in the direction of the inlet end body 53. A position sensor 57is disposed in the center of the locking plate 56. Said position sensor57 comprises a piston 80 displaceably passed in an axial bore 84 of arotating spindle 10 for determining the position of said rotatingspindle.

In the area of the central body, and partially also in the area of theoutlet end body 54, both are surrounded by an outer sleeve 68 alongtheir outer circumference. Said outer sleeve 68 is attached at least tothe outlet end body 54, e.g. by welding. The locking plate 56 ispartially inserted into the outer sleeve 68, where it is sealed bycorresponding sealing members. The outer sleeve 68 comprises (see alsoFIG. 2) three radial extensions 70, 71 and 72. Said extensions extendwith their ends 73 to an inner wall 69 of the flow channel 6. The radialextensions 70 to 72 comprise openings through which lines 81, such aselectrical wires, supply lines, instrument leads or the like, can bepassed from outside the housing 4. The lines 81 are screwed to thehousing 4 externally thereof by means of a terminal 87.

An adjusting means 8 is arranged in the interior space 14 of the centralbody 52. Said adjusting means 8 comprises a recirculating ball nut 9,the rotating spindle 10 and an actuating piston 27. The recirculatingball nut 9 is arranged in a turning sleeve 11 and connected therewith ina rotation-resistant manner. The turning sleeve comprises a radiallyinwardly protruding shoulder 12, which closely fits to a correspondinglyradially outwardly protruding contact flange 13 of the recirculatingball nut 9 in the position illustrated in FIG. 1. The contact flange 13of the recirculating ball nut 9 is arranged approximately centrally onthe recirculating ball nut 9 in an axial direction 32. Via shoulder 12and contact flange 13 the recirculating ball nut 9 and the turningsleeve 11 are removably attached to each other by means of a screwconnection 60 from a number of studs.

The turning sleeve 11 is rotatably mounted in the central body 52 bymeans of a pivot bearing means 17 between its outer wall 15 and a wall16 of the interior space 14. The pivot bearing means 17 is formed, forinstance, by at least one ball bearing 18. For fixing the turning sleeve11 and thus the recirculating ball nut 9 in an axial direction 32 a ringnut 23 is screwed onto a screwing end 24 of the turning sleeve 11 facingthe inlet 2. In its unscrewed position the ring nut 23 fits closely toone end 19 of the pivot bearing means 17. A stop 25 of the turningsleeve II is associated with the other end 21 of the pivot bearing means17. A spacer ring 26 is arranged between said stop 25 and the end 21 ofthe pivot bearing means 17. Moreover, end 21 is partially adjacent ashoulder 20 of the interior space 14.

The pivot bearing means 17 Is fixed in an axial direction 32 relative tothe central body 52 by closely fitting to a shoulder 20 on one hand andby a retainer ring 22 on the other hand.

Via the screw connection 60 a driving toothed wheel 59 is likewiseconnected with the turning sleeve 11 and the recirculating ball nut 9 ina rotation-resistant manner. Said driving toothed wheel is constructedas worm gear 63 being engaged with a corresponding worm shaft 64.

Inside the recirculating ball nut 9 the rotating spindle 10 is mountedrotatably and displaceably in an axial direction 32. The rotatingspindle 10 protrudes with its end 28 from the recirculating ball nut 9in the direction of the outlet 3. At this end 28 the rotating spindle 10is detachably connected to the actuating piston 27. The connection isrealized by a form-fitted engagement of the end 28 with acorrespondingly facing end 29 of the actuating piston 27, and byadditionally screwing the two ends together with studs 85.

The actuating piston 27 is passed through the outlet end body 54 to theflow restrictor 7. The actuating piston 27 protrudes into the bearingbore 37 and is inserted at its free end 43 into an end bore 44 of theflow restrictor 7, where it is screwed in a screwed position 46. Thescrewed, position 46 is defined by a radially outwardly protruding ringflange of the actuating piston 27 fitting closely to a correspondingradially inwardly protruding shoulder 45 of the end bore 44.

The bore 44 is formed in an insertable cylinder 38 of the flowrestrictor 7. A hollow cylinder 34 joins with its end 36 the insertablecylinder 38 in the direction of the outlet 3, whereby the hollowcylinder 34 forms a perforated panel 30 with a plurality of holes 31 inits cylinder wall 35. In an axial direction 32 the holes 31 havedifferent diameters 33. A number of holes 31 with the same diameters 33is arranged along corresponding circumferential lines of the hollowcylinder 34. In the position illustrated in FIG. 1 no fluidic connectionis provided between the flow channel 6 and the outlet 3 through theperforated panel 30. The hollow cylinder 34 is pushed forward into acylindrical portion 40 of outlet 3, where the holes 31 are sealed asagainst the flow channel 6 by means of a sealing sleeve 42 forming aninner wall 41 of the cylindrical portion 40.

The hollow cylinder 34 and the insertable cylinder 38 have identicalouter diameters 39. At least one sealing member 49 is arragened betweenthe insertable cylinder 38 and an inner wall 50 of the bearing bore 37.Said element seals the bearing bore 37 against the flow channel 6.

A guide bore 47 and a flow channel 51 are formed in the insertablecylinder 38 parallel to the end bore 44. The guide bore 47 serves todisplaceably accommodate a guide pin 48. Said guide pin 48 is insertedinto the guide bore with one of its ends and fastened in the outlet endbody 44 with its other end. The flow channel 51 connects the interior ofthe hollow cylinder 34 with the bearing bore 37.

A screwed sleeve 86 is arranged inside the end bore 44, into which thefree end 43 of the actuating piston 27 can be screwed and whichcomprises the shoulder 45. It is also possible that the screwing andpositioning of the free end 43 of the actuating piston 27 is realizeddirectly inside the end bore 44 without interconnecting the screwedsleeve 86.

FIG. 2 is a section along line II-II through FIG. 1. Said figureparticularly shows an electric drive 58 for the recirculating ball nut9, which comprises two electric motors 61 and 62. In FIG. 1 and FIG. 2identical parts have been provided with identical reference numbers andare partly explained in connection with one figure only.

The electric motors 61, 62 are arranged in a transverse bore 77 of thecentral body 52. The transverse bore 77 extends perpendicularly to theaxial direction 32 or, respectively, perpendicularly to the rotatingspindle 10. The worm shaft 64 is rotatably mounted inside the transversebore 77. The worm shaft 64 comprises two end sections 65, 66 each ofwhich is associated with an electric motor 61, 62. Each of the endsections of the shaft 65, 66 is constructed as a driving axle 67rotatably received in the corresponding electric motor 61, 62. Adjacentthe electric motors 61, 62 the worm shaft 64 is rotatably mounted bymeans of at least a radial bearing 82 and a radial bearing 83 on its endsections 65, 66. The transverse bore 77 comprises open ends 78, 79,wherein a radial extension 71, 72 of the outer sleeve 68 is associatedwith each of said ends. Corresponding lines 81 are passed through saidradial extensions 71, 72 to the transverse bore 77 from outside thehousing.

The electric motors 61, 62 are synchronized with each other so as todrive the worm shaft 64 at the same time. The electric motors may bestepper motors or other motors, and the synchronization may be realizedelectronically or by means of software.

In the open ends 78, 79 the electric motors 61, 62 are detachablyfastened and connected with the corresponding lines 81 for supply andcontrol purposes.

The operation of the pressure reducer according to the invention willhereinafter be briefly explained by means of the figures.

For adjusting the flow restrictor 7 in the direction of the inlet 2, theelectric motors 61, 62 are operated by remote control. When operatingthe electric motors 61, 62 the worm shaft 64 rotates correspondingly,and so does, via the engagement thereof with the worm gear 63, therecirculating ball nut 9. When the recirculating ball nut 9 rotates, therotating spindle 10 is displaced in an axial direction 32. In FIG. 1 therotating spindle 10 and, correspondingly, the flow restrictor 7 areillustrated in a locked position, in which no fluidic connection betweenthe flow channel 6 and the outlet 3 is provided.

Given a corresponding rotation of the recirculating ball nut 9 therotating spindle 10 and likewise the actuating piston connectedtherewith is, according to FIG. 1, displaced to the right-hand side inthe direction of the inlet 2. By said displacement the flow restrictor 7connected with the free end 43 of the actuating piston 27 is likewisedisplaced in the direction of the inlet 2. Thus, a fluidic connectionbetween the flow channel 6 and the outlet 3 is produced via more orfewer holes 31 with partially different diameters 33. A correspondingflow rate between the flow channel 6 and the outlet 3 is determined bythe number of the holes 31 and the diameters 33 thereof.

If the flow restrictor 7 is again displaced into the position accordingto FIG. 1, a fluidic connection between the flow channel 6 and theoutlet 3 is again correspondingly interrupted.

In accordance with the invention the adjustment of the flow restrictor 7is realized by the rotation of the recirculating ball nut 9 andparticularly by the engagement of the worm gear 63 with the worm shaft64, whereby the worm shaft 64 is rotatable by two synchronized electricmotors 61, 62. Thus, an exact and reproducible displacement of the flowrestrictor 7, especially by remote control, is feasible. Thecorresponding position of the flow restrictor 7 is determined by theaxial displacement of the rotating spindle 10 by the position sensor 57.

1. A pressure reducer comprising: a housing having an inlet and anoutlet, in which a flow-around body is arranged in a flow channelconnecting the inlet and the outlet, a flow restrictor adjustablymounted relative to the flow-around body for varying a flow rate andmovably connected with an adjusting means having a recirculating ballnut substantially fixed in an axial direction and rotatably mounted inthe flow-around body and a rotating spindle axially adjustably mountedin the recirculating ball nut, wherein the rotating spindle is movablyconnected with the flow restrictor, the recirculating ball nut beingdetachably fastened in a turning sleeve rotatably mounted in theflow-around body and the recirculating ball nut being connected with adriving toothed wheel in a rotation-resistant manner, which is rotatableby an electric drive for the movable connection with the recirculatingball nut.
 2. The pressure reducer according to claim 1, wherein theturning sleeve is fixed in a radial direction.
 3. The pressure reduceraccording to claim 1, wherein the turning sleeve and the recirculatingball nut are arranged in an interior space of the flow-around body. 4.The pressure reducer according to claim 1, wherein a cone point of theinlet end body faces in the direction of the inlet and is arrangedparticularly centrally to the inlet.
 5. The pressure reducer accordingto claim 1, wherein the driving toothed wheel is fastened with theturning sleeve and/or the recirculating ball nut by a screwedconnection.
 6. The pressure reducer according to claim 1, wherein thehousing is formed of two parts and the parts of the housing are heldtogether by a clamping ring along their outer circumference.
 7. Thepressure reducer of claim 1, further comprising the flow restrictorbeing adjustably mounted downstream relative to the flow-around body. 8.The pressure reducer according to claim 1, wherein the turning sleeveincludes a radially inwardly, at least partially protruding shoulderclosely fitting to a radially outwardly protruding contact flange of therecirculating ball nut.
 9. The pressure reducer according to claim 8,wherein the shoulder and contact flange are detachably connected witheach other.
 10. The pressure reducer according to claim 1, wherein therotating spindle is connected with an actuating piston being detachablyconnected with the flow restrictor.
 11. The pressure reducer accordingto claim 10, wherein the rotating spindle and the actuating pistonengage each other with their ends facing each other in a form-fittedmanner and/or are screwed to each other.
 12. The pressure reduceraccording to claim 1, wherein the flow-around body directly or an outersleeve arranged thereon includes at least one radial extension extendingto the inner wall of the flow channel.
 13. The pressure reduceraccording to claim 12, wherein electrical wires, supply lines or thelike are passed through the extension into the flow-around body.
 14. Thepressure reducer according to claim 12, wherein the radial extension ispointed at least at its end facing the inlet.
 15. The pressure reduceraccording to claim 1, wherein a pivot bearing means is arranged betweenthe outer wall of the turning sleeve and walls of the interior space ofthe flow-around body.
 16. The pressure reducer according to claim 15,wherein the pivot bearing means includes at least one ball bearing. 17.The pressure reducer according to claim 15, wherein the pivot bearingmeans is detachably fastened on the wall of the interior space.
 18. Thepressure reducer according to claim 15, wherein the pivot bearing meansclosely fits to a shoulder of the wall with one of its ends and is fixedrelative to the wall at least in an axial direction at its other end.19. The pressure reducer according to claim 15, wherein a retaining ringis associated at the other end of the pivot bearing means.
 20. Thepressure reducer according to claim 15, wherein a ring nut can bescrewed onto a screwing end of the turning sleeve.
 21. The pressurereducer according to claim 20, wherein the turning sleeve includes aradially outwardly protruding stop spaced apart from the screwing end.22. The pressure reducer according to claim 21, wherein a spacer ringcan be arranged between the stop and the pivot bearing means.
 23. Thepressure reducer according to claim 1, wherein the flow-around bodyincludes a central body and two end bodies.
 24. The pressure reduceraccording to claim 23, wherein at least the inlet end body facing theinlet is substantially shaped like a circular cone.
 25. The pressurereducer according to claim 23, wherein at least the recirculating ballnut and the turning sleeve are arranged in the substantially cylindricalcentral body.
 26. The pressure reducer according to claim 23, wherein alocking plate is arranged between the central body and the inlet endbody.
 27. The pressure reducer according to claim 26, wherein a positionsensor is arranged approximately centrally to the locking plate.
 28. Thepressure reducer according to claim 1, wherein the electric driveincludes at least one electric motor.
 29. The pressure reducer accordingto claim 28, wherein the driving toothed wheel is constructed as a wormgear being engaged with a worm shaft driven by the electric motor. 30.The pressure reducer according to claim 29, wherein the worm shaft ismovably connected with an electric motor on each of its end sections.31. The pressure reducer according to claim 30, wherein the end sectionof the shaft is constructed as driving axle of the electric motor. 32.The pressure reducer according to claim 30, wherein the end sections ofthe shaft are mounted adjacent the electric motors.
 33. The pressurereducer according to claim 30, wherein the electric motors and the wormshaft are arranged in an outwardly open transverse bore extendingsubstantially perpendicularly to the rotating spindle.
 34. The pressurereducer according to claim 33, wherein a radial extension is associatedwith each of the open ends of the transverse bore.
 35. The pressurereducer according to claim 1, wherein the flow restrictor is an axiallydisplaceable perforated panel.
 36. The pressure reducer according toclaim 35, wherein holes with different diameters are formed in theperforated panel in an axial direction.
 37. The pressure reduceraccording to claim 35, wherein the perforated panel is constructed as ahollow cylinder with holes arranged in the cylinder wall.
 38. Thepressure reducer according to claim 37, wherein the hollow cylinder isdisplaceably mounted in a cylindrical portion of the outlet.
 39. Thepressure reducer according to claim 38, wherein an inner wall of thecylindrical portion is formed by a sealing sleeve.
 40. The pressurereducer according to claim 38, wherein the outlet conically expandsdownstream of the cylindrical portion.
 41. The pressure reduceraccording to claim 37, wherein the hollow cylinder includes at its endfacing the flow-around body an insertable cylinder axially displaceablein a bearing bore.
 42. The pressure reducer according to claim 41,wherein the hollow cylinder and the insertable cylinder have identicalouter diameters.
 43. The pressure reducer according to claim 41, whereinat least one sealing member is arranged between the insertable cylinderand the inner wall of the bearing bore.
 44. The pressure reduceraccording to claim 41, wherein a flow channel intersperses theinsertable cylinder in an axial direction.
 45. The pressure reduceraccording to claim 41, wherein the rotating spindle is connected with anactuating piston being detachably connected with the flow restrictor andwherein a free end of the actuating piston or the rotating spindle isscrewed into an end bore of the insertable cylinder.
 46. The pressurereducer according to claim 45, wherein the end bore includes a shoulderfor defining a screwed position of the free end.
 47. The pressurereducer according to claim 45, wherein a guide bore is formed parallelto the end bore in the insertable cylinder with which a guide pin isdisplaceably engaged.
 48. A pressure reducer comprising: a housingcomprising an inlet, an outlet, and a housing axis extending from theinlet to the outlet; a flow-around body disposed in the housing to atleast partially define an annular chamber in fluid communication withthe inlet and outlet; a moveable flow restrictor disposed in a fluidpathway between the inlet and the outlet; and an actuation mechanismdisposed in the flow-around body, coupled to the moveable flowrestrictor, and configured to at least partially define the position ofthe flow restrictor with respect to the inlet and outlet; and whereinthe actuation mechanism comprises: a first gear configured to rotateabout a first axis; a second gear configured to rotate in response torotation of the first gear and configured to rotate about a second axis;a threaded spindle configured to move in a direction along the secondaxis in response to actuation of second gear to change the position ofthe flow restrictor; wherein the direction of rotational force appliedto the second gear is parallel with the first axis; and an electricdrive; and, the first gear being coupled to the electric drive.
 49. Thepressure reduced of claim 48, wherein the second gear comprises a ringgear fixed in rotation with respect to a ball nut, the ball nut being inengagement with the threaded spindle.
 50. The pressure reducer of claim48, comprising a torque-generating component disposed in the flow-aroundbody.
 51. The pressure reducer of claim 50, wherein thetorque-generating component comprises at least one electric motor.
 52. Apressure reducer comprising: a housing comprising an inlet, an outlet,and a housing axis extending from the inlet to the outlet; a flow-aroundbody disposed in the housing to at least partially define an annularchamber in fluid communication with the inlet and outlet; a moveableflow restrictor disposed in a fluid pathway between the inlet and theoutlet; and an actuation mechanism disposed in the flow-around body,coupled to the moveable flow restrictor, and configured to at leastpartially define the position of the flow restrictor with respect to theinlet and outlet; and wherein the actuation mechanism comprises: a firstgear configured to rotate about a first axis; a second gear configuredto rotate in response to rotation of the first gear and configured torotate about a second axis; a threaded spindle configured to move in adirection along the second axis in response to actuation of second gearto change the position of the flow restrictor; wherein the first andsecond axes respectively extend in first and second planes that arenon-perpendicular with respect to one another and wherein the firstplane is non-perpendicular to the housing axis; and an electric drive;and, the first gear being coupled to the electric drive.